AbstractTitle: Attitudes and norms around sexual behavior and chlamydia among young men in Denmark – a qualitative study. Background: Chlamydia is a sexually transmitted infection, which can have serious health consequences if left undiagnosed and untreated. Reduction in fertility, involuntary childlessness and pregnancy outside of the womb (ectopic pregnancy) are just some of the long term consequences which an untreated chlamydia infection can cause. In 2016 there has been registered 34.085 cases of chlamydia infection in Denmark, which is the highest number registered to date. There is an over representation of chlamydia seen amongst younger people, and thus 84% of all chlamydia cases occurs among young adults in ages from 15-29 years. This can be related to, that this age group has multiple sex partners and avoid using condoms during intercourse. There is no gender difference seen with the risk of infection, however there is fewer men than women who test for chlamydia, and in general men are less worried than women about chlamydia infection. Problem definition: Which attitudes and norms apply to Danish men in ages 15-29 years in relation to sexual behavior and chlamydia, and how can these perspectives be used to increase chlamydia testing and use of condoms among young men as part of a process of change towards a lower prevalence of chlamydia? Method: There has been completed two focus group interviews through an inductive approach to reach empirical results. The focus groups consisted of in all 11 Danish men between ages 19-27 years. The analysis of the collected focus group data depended on thematic analysis supplemented with elements from conversations analysis. A systematic literature search was conducted subsequently to find the existing evidence on the topic. The findings of the studies were used in the discussion of the analysis results. Results: The main themes, that have been identified through the analysis were: 1. Youth culture with the intention of creating sexual behavior, where it appeared, that there was a strong norm amongst young men compared to an acceptance of an unrestrained sexual behavior with multiple sex-partners. There appeared to be a close connection between that behavior and parties with alcohol and social media apps. 2. The concept of risk among young men, where it appeared, that young men had strong attitudes and norms compared to acceptance of, that condoms are not used. There showed an expectation that women used prevention. That could be associated with young men not seeing a risk with sexually transmitted disease, but in a higher grade worried about unwanted pregnancy or other awkward situations. 3. Considerations associated with reducing the prevalence of chlamydia, where it appeared, that the norm among the young men was, that all sex-partners were contacted if a chlamydia infection was detected. Additionally, it suggested that doctors’ information and testing have substance, and that the present chlamydia campaign doesn’t have the right focus in relation to young men. Conclusion: There are more manly norms and attitudes in relation to sexual behavior and chlamydia which should be taken into consideration when there is compiled a process of change in relation to an increase of the manly chlamydia testing rate and condom usage.